1. Field of the Invention
The invention relates generally to lithographic processes and more particularly lithographic processes using a metal mask and heavy high energy particles.
2. Description of the Prior Art
Photo lithographic techniques are widely used in the semiconductor art. Typical prior art processes utilize a mask which included transparent and non-transparent regions. The mask is positioned in overlying relationship with a photo-sensitive (resist) layer. Ultraviolet light is used to expose the portions of the photo-sensitive layer which underlies the transparent portions of the mask to change the molecular structure of these portions. This process has the characteristics that the masks themselves are relatively fragile and the resolution of the system is primarily limited by diffraction of the ultraviolet light. Alternative techniques have been developed using focused electron beams and X-ray which circumvent the diffraction problem. While these processes substantially improve the resolution, they are relatively expensive in that they require sophisticated equipment and have limited throughput.